AU664309B2 - Process and device for producing extrudates from ultra-high molecular weight polyethylene - Google Patents
Process and device for producing extrudates from ultra-high molecular weight polyethylene Download PDFInfo
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- AU664309B2 AU664309B2 AU48693/93A AU4869393A AU664309B2 AU 664309 B2 AU664309 B2 AU 664309B2 AU 48693/93 A AU48693/93 A AU 48693/93A AU 4869393 A AU4869393 A AU 4869393A AU 664309 B2 AU664309 B2 AU 664309B2
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- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 title claims abstract description 8
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 title claims abstract description 8
- 238000000034 method Methods 0.000 title claims description 25
- 230000015556 catabolic process Effects 0.000 claims abstract description 4
- 238000006731 degradation reaction Methods 0.000 claims abstract description 4
- 229920000642 polymer Polymers 0.000 claims abstract description 4
- 239000011148 porous material Substances 0.000 claims abstract description 3
- 239000008187 granular material Substances 0.000 claims abstract 2
- 230000007704 transition Effects 0.000 claims description 19
- 238000010008 shearing Methods 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 13
- 230000006837 decompression Effects 0.000 claims description 7
- 238000000196 viscometry Methods 0.000 claims description 3
- 230000010006 flight Effects 0.000 claims description 2
- 235000009917 Crataegus X brevipes Nutrition 0.000 claims 1
- 235000013204 Crataegus X haemacarpa Nutrition 0.000 claims 1
- 235000009685 Crataegus X maligna Nutrition 0.000 claims 1
- 235000009444 Crataegus X rubrocarnea Nutrition 0.000 claims 1
- 235000009486 Crataegus bullatus Nutrition 0.000 claims 1
- 235000017181 Crataegus chrysocarpa Nutrition 0.000 claims 1
- 235000009682 Crataegus limnophila Nutrition 0.000 claims 1
- 235000004423 Crataegus monogyna Nutrition 0.000 claims 1
- 240000000171 Crataegus monogyna Species 0.000 claims 1
- 235000002313 Crataegus paludosa Nutrition 0.000 claims 1
- 235000009840 Crataegus x incaedua Nutrition 0.000 claims 1
- 210000002837 heart atrium Anatomy 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 claims 1
- 239000000463 material Substances 0.000 description 9
- 238000000465 moulding Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 239000004698 Polyethylene Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- -1 polyethylenes Polymers 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- WFWLQNSHRPWKFK-UHFFFAOYSA-N Tegafur Chemical compound O=C1NC(=O)C(F)=CN1C1OCCC1 WFWLQNSHRPWKFK-UHFFFAOYSA-N 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000011089 mechanical engineering Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 230000003685 thermal hair damage Effects 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
- B29C48/397—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using a single screw
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/625—Screws characterised by the ratio of the threaded length of the screw to its outside diameter [L/D ratio]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/535—Screws with thread pitch varying along the longitudinal axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/67—Screws having incorporated mixing devices not provided for in groups B29C48/52 - B29C48/66
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/68—Barrels or cylinders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
- B29K2023/04—Polymers of ethylene
- B29K2023/06—PE, i.e. polyethylene
- B29K2023/0658—PE, i.e. polyethylene characterised by its molecular weight
- B29K2023/0683—UHMWPE, i.e. ultra high molecular weight polyethylene
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
For producing extrudates, such as profiles or granules, pulverulent or small-particulate ultrahigh molecular weight polyethylene is processed on single-screw extruders. By using a screw with specific geometry, the thermal degradation of the polymer to form low molecular weight products is avoided. Furthermore, profiles are obtained which have a flawless surface, are free of voids and pores and have no internal stresses. <IMAGE>
Description
r r 4 l L~ P'/UU/U 28/5/9 Regulation 3.2(2) AUSTRALIA s S Patents Act 1990
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: f fI 4 a 4 Invention Title: PROCESS AND DEVICE FOR PRODUCING EXTRUDATES FROM ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE 4444 4 4 4 44 4 0 0 444a 4 4. 9 4994 4 4 The following statement is a full description of this invention, including the best method of performing it known to :-US Process and device for producing extrudates from ultra-hich molecular weight polvethvlene The present invention relates to a process for producing extrudates from ultra-high molecular weight polyethylene (PE-UHMW) on screw extruders and a device for carrying out this process.
PE-UHMW grades have a special position among polyethylenes. By these grades are meant linear polyethylenes obtained by the low pressure process and having an average molecular weight, measured by viscometry, of at least 1 x 106 g/mol, in particular 2.5 x 10 6 g/riol up to approximately 1 x 107 g/mol. A process for determining such high molecular weights is described, for example, in CZ-Chemische Technik 4 (1974), 129 ff.
Ultra-high molecular weight polyethylene is distinguished by a range of physical characteristic data which open up to it a variety of possible applications. Emphasis can be placed on its high wear resistance, its low coefficient of friction with respect to other materials and its outstanding toughness behavior. Furthermore, it is remarkably resistant to numerous chemicals.
Because of its favorable mechanical, thermal and chemical behavior, PE-UHMW is used in a wide variety of fields of application as a versatile material. Examples which can 4 0 0 be quoted are the textile industry, mechanical engineering, the chemical industry and mining.
C 0 cI The possible uses of this material are limited by the fact that its processing in ram extruders and the conventional single-screw or multi-screw extruders to give moldings does not always lead to satisfactory results.
In order to extrude PE-UHMW as gently as possible, i.e.
without impairing its mechanical properties, ram extruders are widely used. Despite its many advantages, this processing method does not meet all requirements. In ~I lu~ particular, the ram-stroke marks occurring on the molding are troublesome and not always tolerable.
The hollow bodies and profiles produced from PE-UHMW on screw extruders do not have these disadvantages. However, the high molecular weight polymer is greatly overheated even at medium screw speeds. As a consequence of the high viscosity of the melt, which is only slightly reduced even with increase of temperature, a very large proportion of the mechanical energy supplied to the screw is transformed by friction into heat. The heating of the material which this causes can be so significant that it leads to thermal damage to the plastic as a result of degradation or decomposition, i.e. by cleavage of the molecular chains, and thus to a reduction in the average molecular weight. Whereas the throughput, i.e. the amount of extrudate transported per unit time, increases approximately proportionally to the screw speed, the temperature increases overproportionally. For this reason, PE-UHMW can only be extruded on screw extruders of conventional design at low screw speed. However, the process then becomes uneconomical and unsuitable for many industrial fields of application.
EP-A-01 90 878 discloses the processing of ultra-high molecular weight polyethylene in a single-screw extruder.
*44n S 25 The process consists in extruding molten PE-UHMW through a die with a length/diameter ratio of at least 10. The extrudates are taken off with a stretch ratio of at least 1, preferably 8 to 30:1. This method is only suitable for 30 producing stretched filaments with a small diameter and at very low output rates.
The object was therefore to discover conditions for the extrusion of PE-UHMW and to match them to one another such that the above-described disadvantages are avoided.
This object is achieved by the present invention. It consists of a process for producing extrudates from pulverulent or small-particulate ultra-high molecular
L
i i i c~ 111~--~ -3 weight polyethylene with an average molecular weight, measured by viscometry, of at least 1 x 106 g/mol in a single-screw extruder the screw shaft of which is arranged into a feed zone, a transition zone, and a (*ischarge zone. It is characterized in that the feed zone is a two-flight screw section and is formed from a transport region the length of which is 4 to 16 times the screw diameter and from a decompression region the length of which is 5 to 18 times the screw diameter, the transition zone consists of a shearing region the length of which is 1 to 2.5 times the screw diameter and the discharge zone comprises a mixing region the. length of which is 1 to 4 times the screw diameter.
The new process not only ensures that the polymer is processed gently, i.e. without thermal degradation: in addition, profiles having perfect surfaces which are free of voids and pores and have no internal stresses are obtained. The chosen screw geometry also ensures that the polymer is transported without disturbance over the entire speed range available to the extruder and is continuously fed to the shaping die. It permits a high material throughput and is correspondingly very economical.
According to the invention, the PE-UHMW is used in a pulverulent or small-particulate form. By this is meant the particles obtained in the polymerization process, but also particles, comminuted by mechanical treatment or other means or else coarsened, of the direct polymerization product.
S I The conveying of the PE-UHMW through the extruder takes place at temperatures of 140 to 300 0 C, preferably 160 to 180 0 C. The required h.at is fed to the material in two ways: internally due to its mechanical stressing, as frictional heat, and externally via heating devices.
According to the invention, the feed zone is designed as r ~Ii 4 a two-flight screw part and is subdivided into two regions. In the first region the thermoplastic is received, transported and compressed. The length of the feed zone is 4 to 16 times and preferably 4 to 8 times the screw diameter. It is followed by a second region in which, by changing the flight depth of the lands, a decompression takes place. This region has a length of to 18 times, preferably 6 to 12 times, the screw diameter. The width of the lands is constant over the entire feed zone and is 0.05 to 0.09 times, preferably 0.055 to 0.065 times, the screw diameter. The ratio of the flight depth in the feed zone to the flight depth in the discharge zone is 0.6:1 to 1:1, preferably 0.68:1 to 0.76:1, the maximum flight depth over the entire length of the screw being 2.5 to 6, preferably 3.5 to 5 mm.
From the feed zone the PE-UHMW, already heated above the crystallite melting range by the frictional forces, passes into the transition zone. The latter consists of a shearing region formed by a shearing element of conventional design. Preferably the shearing element is provided with longitudinal grooves. In it, the melt stream flows through a defined shearing gap completing the plastication and the homogenization of the thermo- $t11 S4 plastic. The length of the shearing region is 1 to 25 times, preferably 1.5 to 2 times, the screw diameter. The 0040 0 screw clearance, i.e. the distance of the shearing element from the barrel wall, is 0.20 to 0.50 mm, preferably 0.25 to 0.35 mm.
4.400 o 0 In a proven embodiment of the new process, a transport region can follow the shearing region of the feed zone.
The tranisport region is designed as a single-flight screw section and has a length of up to 4.5 times, preferably 3 to 4 times, the screw diameter. The land width is 0.08 to 0.15 times, in particular 0.10 to 0.12 times, the screw diameter.
The material coming from the transition zone is received i. i.
pr -7 i by the discharge zone or metering zone. The latter has the function of a mixing region and its length corresponds to 1 to 4 times, in particular to 2 to 3 times, the screw diameter. Preferably the mixing region is formed by a screw part provided with knobs or pins.
It has proven suitable for the mixing region in the transition zone also to be followed by a single-flight screw part as transport region. The length of the transition zone is up to 2 times the screw diameter and the land width is, as in the transport region of the transition zone, 0.08 to 0.15 times, in particular 0.10 to 0.12 times, the screw diameter. After leaving the transition zone, whether directly via the mixing region or via the transport region, the thermoplastic material is fed to the die.
The invention further relates to a device for carrying out the new process. It comprises a barrel tube in the bore of which a screw shaft is rotatably mounted and which is provided,- in the coolable feed region, with pockets or grooves extending in the longitudinal direction and which has a heatable transport part and an adjoining die.
This device is characterized in that the screw shaft has two flights in the fred region and is formed by a transport region with a length which is 4 to 16 times, preferably 4 to 8 times, the screw diameter and by a decompression region with a length which is 5 to 18 times, preferably 6 to 12 times, the screw diameter, in that, in a transition zone, the scre shaft consists of a shearing region the length of which is 1 to 2.5 times, preferably 1.5 to 2 times, the screw diameter and in that, in a discharge zone, the screw shaft comprises a mixing region the length of which is 1 to 4 times, preferably 2 to 3 times, the screw diameter.
In proven embodiments of the new device, in the ii i l 6 transition zone, the shearing region and/or, in the discharge zone, the mixing region are in each case followed by a transport region in the form of a singleflight screw section. The length of the latter is, in the transition zone, up to 4.5 times, preferably 3 to 4 times, the screw diameter and, in the discharge zone, up to 2 times the screw diameter.
The device according to the invention is provided in the feed region with a number of axial grooves distributed uniformly around the circumference of the barrel, which axial grooves, in the region of the feed opening, can be enlarged in the form of pockets. The length of the grooves, which are preferably rectangular in cross section, is 3 to 3.5 times the screw diameter. They have a depth of 4.5 to 6 mm, in particular 5 to 5.5 mm, and a width of 5 to 8.5 mm, in particular 6 to 7 mm. The number of grooves is dependent on the diameter of the screw. For a screw diameter of 150 mm, for example, it is 6 to 12, preferably 8 to In a proven embodiment of the new device, the pockets are to 20 mm longer than the diameter of the screw and their depth is 2 to 4 mm, preferably 3 to 3.5 mm. The i cpockets murge into the grooves at an angle of 6 to preferably 7 to rrco In order to ensure a continuous stream of pulverulent or 000 small-particulate material, the feed opening should have a length of 1.4 to 1.8 times, preferably 1.5 to 1.6 Yi times, the screw diameter and its width should be approximately equal to the screw diameter or exceed it by up to 4 mm.
The material leaving the b?,ial is plasticated and fed to the shaping die. The die is provided with heating and cooling devices which permit the heat to be supplied and/or removed in a controlled manner. The temperatures along the die are between 300 0 C at the inlet and 130 0 C at Oh- -i 1 -7the end, preferably between 180 and 1401C. In the direction of the die outlet, the cross section of the flow channel tapers. This results in a pressure rise in the die land, which pressure rise is adjusted by corresponding adjustment of the cross-sectional size such that the thermoplastic particles sinter together into a homogeneous mass and the moldings obtain a smooth surface.
The extrudate emerging from the die is led into a cooling die in which its surface is cooled down to temperatures below the crystallite melting point, i.e. below approximately 130 0 C. After leaving the cooling die, the moldings are guided by appropriate devices, e.g. braking lips or braking flaps or by suitable measures, such that a force acting opposite to the extrusion direction results. This force ensures, in the cooling zone, that the molding comes into contact on all sides with the coolant separated from it by a wall, so that the heat removal takes place uniformly and the occurrence of stresses in the molding is avoided. Further cooling takes place, corresponding to the prior art, in a water bath which is uniformly temperature controlled or subdivided into different temperature zones.
I
oa'*In a special embodiment of the device for carrying out O 25 the process, the extrudate is shaped into strands by means of an apertured plate. The thickness of the 00 apertured plate Is conventionally 10 to 50 mm, preferably 30 to 40 mm and the bores have diameters of 1.5 to 5 mm, 00 s4 0 in particular 2 to 4 mm, diameter. They are expediently equipped with conical inlets, the inlet angle being to 50, preferably 0.8 to 1.50. The strands emerging from the apertured plate are pelletized by means of conventional commercial pelletizing devices, such as strand pelletizers, hot-cut pelletizers, water-cooled die face pelletizers or underwater pelletizers.
I 8 Description of the drawing The attached drawing shows a screw shaft of the type used in the device for carrying out the new process. The screw shaft is arranged into a feed zone, a transition zone, and a discharge zone. The feed zone is formed from a transport region 1 and a decompression region 2. The transition zone consists of a shearing region 3 which can be followed by a transport zone 4. The material coming from the transition zone is received by the discharge (or meL ring) zone comprising a mixing region 5 which also can be followed by a transport zone 6.
co 0 I
Claims (11)
1. A process for producing extrudates from pulverulent to small-particulate ultra-high molecular weight polyethylene having an average molecular weight, measured by viscometry, of at least 1 x 106 g/mol in a single-screw extruder the screw shaft of which is arranged into a feed zone, a transition zone and a discharge zone, wherein the feed zone is a two- flight screw section and is formed from a transport region the length of which is 4 to 16 times the screw diameter and a decompression region the length of which is 5 to 18 times the screw diameter, the transition zone consists of a shearing region the length of which is 1 to 2.5 times the screw diameter and the discharge zone comprises a mixing region the length of which is 1 to 4 times the screw diameter.
2. The process as claimed in claim 1, wherein, in the feed zone, the length of the transport region is 4 to 8 times the screw diameter and the length of the decompression region is 6 to 12 times the screw diameter, in the trans.tion zone, the length of the shearing region is 1.5 to 2 times the screw diameter and, in the discharge zone, the length of the mixing region is 2 to 3 times the length of the screw diameter.
3. The process as claimed in claim 1 or 2, wherein, in the transition zone, the shearing region is followed by a transport region which is designed as a single- flight screw section and the length of which is Up to 4.5 times, preferably 3 to 4 times, the screw diameter.
4. The process as claimed in one or more of claims 1 to 3, wherein, in the discharge zone, the mixing region is followed by a transport region which is designed as a single-flight screw section and the length of which is up to 2 times the screw diameter. ~o 6 a. o *a a L Ci L 'i F' u~r*lrrrrr; The process as claimed in one or more of claims 1 to 4, wherein the ratio of the flight depth of the screw in the feed zone to the flight depth in the discharge zone is 0.6:1 to 1:1, preferably 0.68:1 to 0.76:1.
6. The process as claimed in one or more of claims 1 to wherein the maximum flight depth over the entire length of the screw is 2.5 to 6 mm, preferably to 5 mm.
7. The process as claimed in one or more of claims 1 to 6, wherein the screw clearance in the shearing region of the screw is 0.20 to 0.50 mm, preferably 0.25 to 0.35 mm.
8. A device for carrying out the process as claimed in any of claims 1 to 7, comprising of a barrel tube in the bore of which a screw shaft is rotatably mounted and which is provided, in the coolable feed region, with pockets or grooves extending in the i longitudinal direction and which has a heatable transport part and an adjoining die, wherein the screw shaft has two flights in the feed region and is formed by a transport region with a length which is 4 to 16 times, preferably 4 to 8 times, the screw diameter and by a decompression region with a length which is 5 to 18 times, preferably 6 to 12 times, the screw diameter, wherein, in a transition zone, OF said screw shaft consists of a shearing region the O h length of which is 1 to 2.5 times, preferably 1.5 to 2 times, the screw diameter and wherein, in a discharge zone, said screw shaft comprises a mixing region the length of which is 1 to 4 times, preferably 2 to 3 times, the screw diameter.
9. The device as claimed in claim 8, wherein, in the transition zone, the shearing region is followed by a transport region in the form of a single-flight I 11 screw section the length of which is up to times, preferably 3 to 4 times, the screw diameter. The device as claimed in claim 8 or 9, wherein, in the discharge zone, the mixing region is followed by a transport region in the form of a single-flight screw section the length of which is up to 2 times the screw diameter.
11. The device as claimed in one or more of claims 8 to wherein the grooves in the feed region are rectangular in cross section, their length is 3 to times the screw diameter, their depth is 4.5 to 6 mm, in particular 5 to 5.5 mm, and their width is to 8.5 mm, in particular 6 to 7 mm.
12. The device as claimed in one or more of claims 8 to 11, wherein the pockets are 15 to 20 mm longer than the diameter of the screw and their depth is 2 to 4 mm, preferably 3 to 3.5 mm.
13. The device as claimed in one or more of claims 8 to 12, wherein the die is designed as an apertured plate with a thickness of 10 to 50 mm, preferably to 40 mm, and is provided with bores of 1.5 to 5 mm, preferably 2 to 4 mm, in diameter. DATED this 29th day of September 1993. S« HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEM!;RK ATTORNEYS "THE ATRIUM" 290 BURWOOD ROAD HAWTHORN. VIC. 3122. c i i Abstract For the production of extrudates such as profiles or granules, pulverulent or finely divided ultra-high molecular weight polyethylene is processed on single screw extruders. By the use of a screw with a- specific geometry, the thermal degradation of the polymer into low molecular weight products is avoided. Furthermore, profiles are obtained which have a perfect surface, are free of voids and pores and have no internal stresses. l i 1 L -1 c-
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4232988A DE4232988A1 (en) | 1992-10-01 | 1992-10-01 | Method and device for the production of extrudates from ultra high molecular weight polyethylene |
| DE4232988 | 1992-10-01 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4869393A AU4869393A (en) | 1994-04-14 |
| AU664309B2 true AU664309B2 (en) | 1995-11-09 |
Family
ID=6469364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU48693/93A Ceased AU664309B2 (en) | 1992-10-01 | 1993-09-30 | Process and device for producing extrudates from ultra-high molecular weight polyethylene |
Country Status (15)
| Country | Link |
|---|---|
| US (1) | US5449484A (en) |
| EP (1) | EP0590507B1 (en) |
| JP (1) | JPH0790589B2 (en) |
| KR (1) | KR940008856A (en) |
| AT (1) | ATE145854T1 (en) |
| AU (1) | AU664309B2 (en) |
| BR (1) | BR9303879A (en) |
| CA (1) | CA2106820C (en) |
| DE (2) | DE4232988A1 (en) |
| DK (1) | DK0590507T3 (en) |
| ES (1) | ES2097412T3 (en) |
| PL (1) | PL173458B1 (en) |
| SG (1) | SG44817A1 (en) |
| TW (1) | TW259749B (en) |
| ZA (1) | ZA937098B (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0657268B1 (en) * | 1993-11-05 | 1999-05-26 | Battenfeld GmbH | Method and apparatus for injection moulding of multilayered articles |
| FI965182A (en) | 1996-04-04 | 1997-10-05 | Conenor Oy | Process and apparatus for producing an extruded plastic product and plastic product |
| US5573331A (en) * | 1995-09-08 | 1996-11-12 | Lin; Ping H. | Multiple-stage screw for blending materials |
| US6712495B2 (en) * | 2001-11-20 | 2004-03-30 | E. I. Du Pont De Nemours And Company | Mixing apparatus |
| DE10217232B4 (en) * | 2002-04-18 | 2004-08-19 | Ticona Gmbh | Process for the production of filled granules from polyethylene of high or ultra-high molecular weight |
| US7803450B2 (en) * | 2006-07-21 | 2010-09-28 | Quadrant Epp Ag | Production of UHMWPE sheet materials |
| US7758796B2 (en) * | 2006-07-21 | 2010-07-20 | Quadrant Epp Ag | Production of UHMWPE sheet materials |
| US7758797B2 (en) * | 2006-07-21 | 2010-07-20 | Quadrant Epp Ag | Production of UHMWPE sheet materials |
| US7736579B2 (en) * | 2006-07-21 | 2010-06-15 | Quadrant Epp Ag | Production of UHMWPE sheet materials |
| WO2013034582A1 (en) * | 2011-09-05 | 2013-03-14 | Stichting Dutch Polymer Institute | Process for the melt extrusion of ultra high molecular weight polyethylene |
| KR101332980B1 (en) * | 2011-12-27 | 2013-11-25 | 김영수 | Method of Extruding Very High Molecular Weight Polyethylene |
| SK6879Y1 (en) | 2013-04-02 | 2014-09-04 | Konstrukta Industry A S | Decompression screw for rubber mixtures processing |
| KR101665531B1 (en) * | 2015-12-18 | 2016-10-24 | 홍국선 | Extruder for 3d-printer and 3d-printer comprising the same |
| CN110126233A (en) * | 2019-05-05 | 2019-08-16 | 北京化工大学 | A kind of high shear interface multiplier |
| NL2023518B1 (en) * | 2019-07-17 | 2021-02-22 | Tekalen Holding Verwaltungs Gmbh | A method for continuously manufacturing UHMWPE products |
| EP3848178B1 (en) * | 2020-01-08 | 2022-03-09 | Novoplast Schlauchtechnik GmbH | Method for the production of plastic hoses |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2311946A1 (en) * | 1973-03-07 | 1974-09-19 | Siemens Ag | Screw press for crosslinkable olefin polymers - with rows of studs on screw in mixing zone |
| FR2669260A1 (en) * | 1990-11-21 | 1992-05-22 | Conditionnement Ind Sa | EXTRUDER SCREW FOR POLYETHYLENE. |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3486192A (en) * | 1967-03-24 | 1969-12-30 | Union Carbide Corp | Apparatus for extrusion of thermoplastics |
| US3650652A (en) * | 1970-05-05 | 1972-03-21 | Feed Screws Inc | Apparatus for extruding plastic material |
| DE2346032A1 (en) * | 1973-09-10 | 1975-03-20 | Siemens Ag | SCREW PRESS WITH IMPROVED FEEDING BEHAVIOR |
| JPS57128209A (en) * | 1981-01-26 | 1982-08-09 | Toyobo Co Ltd | Uniform dispersing method |
| JPS6153216A (en) * | 1984-08-23 | 1986-03-17 | Rikagaku Kenkyusho | Hypertension preventive |
| US4733970A (en) * | 1985-09-09 | 1988-03-29 | Sterling Extruder Corporation | Extruder screw |
| DE3915603C1 (en) * | 1989-05-12 | 1990-03-15 | Basf Ag, 6700 Ludwigshafen, De | |
| US4994223A (en) * | 1989-06-16 | 1991-02-19 | Bomatic, Inc. | Extruder screw and method for the extrusion of thermally sensitive thermoplastic materials |
| GB9027699D0 (en) * | 1990-12-20 | 1991-02-13 | Univ Toronto | Process for the continuous production of high modulus articles from polyethylene |
| TW254883B (en) * | 1991-04-03 | 1995-08-21 | Mitsui Petroleum Chemicals Ind |
-
1992
- 1992-10-01 DE DE4232988A patent/DE4232988A1/en not_active Withdrawn
-
1993
- 1993-08-27 TW TW082106972A patent/TW259749B/zh active
- 1993-09-22 JP JP5236545A patent/JPH0790589B2/en not_active Expired - Lifetime
- 1993-09-23 EP EP93115306A patent/EP0590507B1/en not_active Expired - Lifetime
- 1993-09-23 SG SG1996008199A patent/SG44817A1/en unknown
- 1993-09-23 BR BR9303879A patent/BR9303879A/en unknown
- 1993-09-23 AT AT93115306T patent/ATE145854T1/en not_active IP Right Cessation
- 1993-09-23 DK DK93115306.8T patent/DK0590507T3/en active
- 1993-09-23 DE DE59304662T patent/DE59304662D1/en not_active Expired - Lifetime
- 1993-09-23 ES ES93115306T patent/ES2097412T3/en not_active Expired - Lifetime
- 1993-09-23 CA CA002106820A patent/CA2106820C/en not_active Expired - Lifetime
- 1993-09-24 PL PL93300489A patent/PL173458B1/en unknown
- 1993-09-24 KR KR1019930019628A patent/KR940008856A/en not_active Application Discontinuation
- 1993-09-24 ZA ZA937098A patent/ZA937098B/en unknown
- 1993-09-29 US US08/128,814 patent/US5449484A/en not_active Expired - Lifetime
- 1993-09-30 AU AU48693/93A patent/AU664309B2/en not_active Ceased
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2311946A1 (en) * | 1973-03-07 | 1974-09-19 | Siemens Ag | Screw press for crosslinkable olefin polymers - with rows of studs on screw in mixing zone |
| FR2669260A1 (en) * | 1990-11-21 | 1992-05-22 | Conditionnement Ind Sa | EXTRUDER SCREW FOR POLYETHYLENE. |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0790589B2 (en) | 1995-10-04 |
| KR940008856A (en) | 1994-05-16 |
| CA2106820A1 (en) | 1994-04-02 |
| TW259749B (en) | 1995-10-11 |
| DE4232988A1 (en) | 1994-04-07 |
| EP0590507A1 (en) | 1994-04-06 |
| DK0590507T3 (en) | 1996-12-23 |
| AU4869393A (en) | 1994-04-14 |
| ZA937098B (en) | 1994-07-21 |
| CA2106820C (en) | 1996-11-12 |
| EP0590507B1 (en) | 1996-12-04 |
| ATE145854T1 (en) | 1996-12-15 |
| PL300489A1 (en) | 1994-04-05 |
| PL173458B1 (en) | 1998-03-31 |
| DE59304662D1 (en) | 1997-01-16 |
| BR9303879A (en) | 1994-04-12 |
| SG44817A1 (en) | 1997-12-19 |
| JPH06198714A (en) | 1994-07-19 |
| US5449484A (en) | 1995-09-12 |
| ES2097412T3 (en) | 1997-04-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |